Powder Metal and Cast Valve Seats Inserts

Valve seat inserts are representing a very important component of the valve train in internal combustion engines, as they are the interface between the valve and the cylinder head. Valve and valve seat inserts together serve to seal off the combustion chamber regulating the inlet and exhaust gases. The valve seat insert avoids direct contact of the valve with the cylinder head and absorbs part of the combustion heat which is transferred to the valve by passing it on to the cylinder head. The selection of material of valve seat inserts is of critical importance in order to withstand millions of cycles in high temperatures, stress and corrosive gases and compounds. There is a range of material grades for various engine applications. Federal-Mogul develops their Powder Metal alloys by starting with the melt und producing our own special hard particles and key ingredients.

The valve seat materials are designed using thermodynamic modeling and advanced metallurgical and physical testing to ensure the complex alloys, composites, additives and processing provide components that are thermally stable at exhaust valve seat operating temperature. Sintered materials are inherently porous. We use a technique known as infiltration to fill porous spaces in the valve seat with copper. The copper improves the thermal properties of the component, and improves the machineability of the material. We have added a wear-resistant phase to our valve seat manufacturing process to produce a composite and enhance wear resistance. The wear-resistant phase is highly alloyed, allowing the overall cost of the component to be reduced using dual-layer technology. This process allows the component to be manufactured using a wear-resistant alloy for the working surfaces and a plain iron material used as backing in the nonfunctional portion of the component.

Federal-Mogul offers a wide range of PM alloys meeting the application requirement including several cast option, if requested by the market. The final product can be machined to specification within the cylinder head or delivered in fully finished condition (ready to run). Machinability at customer is supported by specialists to improve tool wear ressitance and related cost. Valve seat inserts must fulfill certain characteristics, such as compressive yield strength, hot hardness, thermal expansion, elevated temperature stability, thermal conductivity, corrosion, adhesisve and abrasive wear resistance and machinability.PM Valve Seat Inserts start with an outer diameter as small as 15mm and range up to 60mm for industrial engines.